CVE-2026-81903Concrete CMS 9.0.0 to 9.5.2 is vulnerable to Stored XSS via Page Container icon
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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Concrete CMS versions 9.0.0 to 9.5.2 stored the Page Container icon value submitted through the dashboard without validating it against the set of known container icons. The unvalidated value was later concatenated into the src attribute of an img tag by a helper that did not encode attribute output, and was rendered raw in the Containers dashboard list and editor views. A user with delegated access to the Page Containers dashboard could store a crafted icon value that broke out of the src attribute and executed script in the authenticated session of another editor or administrator who viewed the list, enabling session token theft and privileged dashboard actions. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.0 with vector CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Andrew Gonzalez for reporting.
- CVSS
- 7.0 HIGH (v4.0, CNA)CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- Weakness (CWE)
- CWE-79
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- ConcreteCMS
- NVD analysis
- Analyzed
- Record last updated
- Sep 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Concrete CMS Concrete CMS concrete_cms:concrete_cms (from the name) | from 9.0.0 through 9.5.2 | CNA record |
concretecms concrete_cms concretecms:concrete_cms | from 9.0.0 before 9.5.3 | NVD |
References
- https://documentation.concretecms.org/developers/introduction/version-history/953-release-notesrelease-notes, broken-link
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.